Biomagnification of DDT through the Benthic and Pelagic Food Webs of Lake Malawi, East Africa: Importance of Trophic Level and Carbon Source
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- 作者：Karen A. Kidd ; Harvey A. Bootsma ; Raymond H. Hesslein ; Derek C. G. Muir ; and Robert E. Hecky
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：January 1, 2001
- 年：2001
- 卷：35
- 期：1
- 页码：14 - 20
- 全文大小：90K
- 年卷期：v.35,no.1(January 1, 2001)
- ISSN：1520-5851
文摘
Lake Malawi, an East African Rift Valley lake, is internationallyrenowned for having the highest diversity of fish speciesin the world, and these cichlids are highly specialized in theirdietary habits. In this lake, tissue stable carbon (
13C)and nitrogen (15N) isotopes can be used over severaltrophic levels to distinguish those consumers relying uponcarbon fixed by either benthic or pelagic primaryproducers. As such, it was possible to contrast thebiomagnification of persistent organochlorines throughthe benthic and pelagic food webs. In 1996 and 1997, food-web organisms were collected from Lake Malawi andanalyzed for organochlorines, 13C and 15N to determinethe factors that affect the biomagnification of contaminantsin a tropical lake. The pesticide DDT was the most predominantpollutant in the biota from Lake Malawi and was foundat the highest concentrations in the largest and fattiest fishspecies. As observed in temperate systems, log-transformed 
DDT concentrations in food-web organismswere significantly predicted by 15N or log lipid (r 2 =0.32 and 0.40, respectively). In addition, the slope of theregression of log DDT versus 15N was significantly higherin the pelagic than the benthic food web. These resultsindicate that pelagic organisms are at greater risk ofaccumulating these pollutants than biota relying uponbenthic primary production.
13C)and nitrogen (15N) isotopes can be used over severaltrophic levels to distinguish those consumers relying uponcarbon fixed by either benthic or pelagic primaryproducers. As such, it was possible to contrast thebiomagnification of persistent organochlorines throughthe benthic and pelagic food webs. In 1996 and 1997, food-web organisms were collected from Lake Malawi andanalyzed for organochlorines, 13C and 15N to determinethe factors that affect the biomagnification of contaminantsin a tropical lake. The pesticide DDT was the most predominantpollutant in the biota from Lake Malawi and was foundat the highest concentrations in the largest and fattiest fishspecies. As observed in temperate systems, log-transformed DDT concentrations in food-web organismswere significantly predicted by 15N or log lipid (r 2 =0.32 and 0.40, respectively). In addition, the slope of theregression of log DDT versus 15N was significantly higherin the pelagic than the benthic food web. These resultsindicate that pelagic organisms are at greater risk ofaccumulating these pollutants than biota relying uponbenthic primary production.